Vehicles, such as rail vehicles, may be configured with truck assemblies including two trucks per assembly, and three axles per truck. The three axles may include at least one powered axle and at least one non-powered axle. The axles may be connected to the truck frame via a dynamic weight control (DWC) mechanisms (e.g., suspension assemblies including one or more actuators) for adjusting a distribution of vehicle weight (including a vehicle body weight and a vehicle truck weight) between the axles. Weight distribution among the powered and non-powered axles may be performed statically by spring system geometry or stiffness and/or dynamically by adjusting an amount of force exerted by the dynamic weight control mechanisms.
An actuator of the DWC mechanism may adjust a vertical force between the axle and truck. While the mechanism may allow some compliance in the vertical direction, constraints in the lateral and/or longitudinal directions may cause excessively high stresses in components of the truck assembly due to forces generated by dynamic motion of the truck, eccentric loads on the truck, etc.
Additionally, in the example of hydraulic actuation, the actual amount of force may not be directly available from measurements. Further, the amount of force that is provided by the hydraulic actuator may be affected differently by dynamic external factors such as rail irregularities, dynamic coupling force changes, and others, depending on the type of control system.